Journey to adopt Cloud-Native DevOps platform Series #1: OfferUp modernized DevOps platform with Amazon EKS and Flagger to accelerate time to market

In this two part series, we discuss the challenges faced by OfferUp, a Digital Native customer, to meet business growth and time-to-market. Their journey involved modernizing their existing DevOps platform, from the traditional monolith virtual machine (VM) based architecture to modern containerized architecture and running cloud-native applications for secured progressive delivery to accelerate time to market. This series will provide strategies, architecture patterns, and technical steps you can adopt to become more agile and innovative like OfferUp has.

OfferUp engineers were using the homegrown DevOps platform to build and release new services on the marketplace platform. In this first post, we discuss the key challenges encountered by OfferUp engineers with the existing DevOps platform, as well as how OfferUp modernized its DevOps platform with Amazon Elastic Kubernetes Service (Amazon EKS) and Flagger, automating production releases with progressive delivery techniques for faster time-to-market with new products and services. Amazon EKS is a managed container service to run and scale Kubernetes applications in the cloud or on-premises.

Previous DevOps architecture

OfferUp is a leading online and mobile customer to customer (C2C) marketplace where users can both buy and sell goods on the platform. Users can browse and purchase products from a broad range of categories, including furniture, clothing, sports equipment, toys, and many more. As a mobile-first company, OfferUp puts a great deal of emphasis on in-person communication between buyers and sellers.

OfferUp built a home grown, self-managed DevOps platform. This platform used a set of manual processes and third-party applications that allows both developers and operations engineers to build and deploy code to a production environment. The DevOps pipeline included topic areas such as source code control, continuous integration/continuous delivery (CI/CD), microservices, as well as development and test Methodologies. The following diagram depicts the previous architecture of OfferUp’s DevOps platform, which was self-managed on Amazon Elastic Compute Cloud (Amazon EC2).

Figure 1: Previous DevOps architecture of OfferUp

OfferUp used GitHub for code repositories. Once the source code was committed in the code repository, Jenkins pulled the source code from code repositories on a scheduled or on-demand basis and built Amazon Machine Images (AMI). The built image was deployed in production by a  custom built deployment tool, Vanaheim, which supports one-box canary deployment and full roll-out deployment strategies. The DevOps engineers used to manually create a deployment job in the Vanaheim portal and then manually monitor the test success rate and service metrics to detect any impact from the deployment. Once the success rate was reached, a full production roll out was performed from the Vanaheim portal.

Key challenges with previous DevOps pipeline

In 2020, OfferUp experienced significant transaction volume growth on its Marketplace platform with the increase of its user base. With OfferUp’s acquisition of LetGo in 2020, there was a need to build a scalable DevOps platform to support future integration and organic growth. The previous DevOps platform, designed and deployed over seven years ago, had reached the limits of its scalability, and could no longer keep up with the platform’s growth. The previous architecture was expensive to run and had a complex infrastructure that made it difficult to upgrade and add new features.

The following key factors drove the push for modernization:

• Manual verification was required to check if the code was correctly deployed in one of the servers in production, and if the deployment was right in one server, then it was rolled out to other production servers. Full Rollout to production wasn’t automated due to frequent failures requiring manual rollbacks.
• The previous platform required a longer deployment time (1–2 hours) due to the authoritative batch process, which sometimes caused delays in releasing and testing of new features.
• The self-managed nature of the Jenkins and Vanaheim clusters was consuming far too much engineering time. Most of the institutional knowledge of this legacy platform was lost over the years and it didn’t align with OfferUp’s philosophy of small DevOps engineering teams. Innovation had stalled partly due to the difficulty of simultaneously upgrading the DevOps platform and releasing new features.

DevOps platform automation with Flagger and Gloo Ingress Controller on Amazon EKS

A key requirement for the next-generation system was that the new architecture would reduce the operational burden on engineering teams, deployment lifecycle, and total cost of ownership. OfferUp evaluated multiple managed container orchestration platforms for its DevOps Platform. It finally selected Amazon EKS for high availability, reducing the average time to deploy a change to the stack from hours to just a few minutes and reducing the complexity in managing and upgrading the Kubernetes cluster. On the Amazon EKS platform, OfferUp uses Flagger, a progressive delivery tool that automates the release process for applications running on Kubernetes. Flagger implements several deployment strategies (Canary releases, A/B testing, and Blue/Green mirroring) using the Gloo Edge ingress controller for traffic routing. Datadog is used as an observability service for monitoring the health of the deployments and effectively managing the canary to progressive delivery. For release analysis, Flagger runs a query on Datadog logs and uses Slack for alerting and notifications. The cloud native technology components of the architecture are described as follows:

Kubernetes and Amazon EKS – Kubernetes is an open-source system for automating the deployment, scaling, and management of containerized applications. Kubernetes is a graduate project in the CNCF. Amazon EKS is a fully-managed, certified Kubernetes conformant service that simplifies the process of building, securing, operating, and maintaining Kubernetes clusters on AWS. Amazon EKS integrates with core AWS services, such as Amazon CloudWatch, Auto Scaling Groups, and AWS Identity and Access Management (IAM) to provide a seamless experience for monitoring, scaling, and load balancing your containerized applications.

Helm – Helm manage Kubernetes applications. Helm Charts define, install, and upgrade even the most complex Kubernetes application. Charts are easy to create, version, share, and publish. If Kubernetes were an operating system, then Helm would be the package manager. Helm is a graduate project in the CNCF and is maintained by the Helm community.

Flagger – Flagger is a progressive delivery tool that automates the release process for applications running on Kubernetes. Flagger implements a control loop that gradually shifts traffic to the canary while measuring key performance indicators such as HTTP requests success rate, requests average duration, and pods health. Based on the set thresholds, a canary is either promoted or aborted and its analysis is pushed to a Slack channel. Flagger became a CNCF project – part of the Flux family of GitOps tools.

Gloo Edge – Gloo Edge is a feature-rich, Kubernetes-native ingress controller. Gloo Edge is exceptional in its function-level routing; its support for legacy apps, microservices, and serverless; its discovery capabilities; and its tight integration with leading open-source projects. Gloo Edge is uniquely designed to support hybrid applications, in which multiple technologies, architectures, protocols, and clouds can coexist.

Observability platform – Datadog’s integrations with Kubernetes, Docker, and AWS will let you track the full range of Amazon EKS metrics, as well as logs and performance data from your cluster and applications. Datadog gives you comprehensive coverage of your dynamic infrastructure and applications with features like auto discovery to track services across containers, sophisticated graphing, and alerting options.

Modernized DevOps architecture

In the new architecture, OfferUp uses Github as a version control tool and Github actions as their CI/CD tool. On every Pull request, tests are run, artifacts are built and stored in the JFrog Artifactory, and docker Images are stored in the Amazon Elastic Container Registry (Amazon ECR). Separate deployment pipelines are triggered based on the environment (dev, staging, and production) of choice. Flagger detects any changes in the version of the application and gradually shifts production traffic to the canary. It measures the requests success rate and average response duration metrics from Datadog to decide full rollout in production. For an application deployment, a canary promotion can be defined using Flagger’s custom resource. Flagger rolls back the deployment when the success rate falls below the defined desired success rate metrics.

Figure 2: Modernized DevOps architecture of OfferUp

With the modernized DevOps platform, OfferUp moved from monolithic to microservice architecture where  front-end applications and GraphQL runs on the Amazon EKS cluster. The production cluster runs 110 services and 650+ pods on 60 nodes. The cluster scales up to 100 nodes with Amazon Auto Scaling group based on the traffic pattern. On the networking front, the cluster has a private endpoint and uses both VPC CNI plugin, and the CoreDNS add-on. There are four Amazon EKS clusters, one each for the production, test, utility, and the staging environments. OfferUp has a plan to explore Karpenter open-source autoscaling project, and it will move new applications to the Amazon EKS cluster, allowing the total node counts to scale up to 200.

Benefits of modernized architecture

The new architecture helped OfferUp make  automated decisions to deploy new releases and improve the time to market while reducing unplanned production downtime

• Faster deployments and Quicker rollbacks – The new architecture reduces the Service Deployment time from one hour down to five minutes, and automates rollback time to five minutes from the manual rollback time of one hour.
• Automate deployment of new releases – The lack of canary deployment processes in the previous architecture required OfferUp engineers to manually intervene to validate the deployment status, which led to administrative overhead and production outages. The canary deployments take care of the traffic shifting by automatically measuring the requests’ success rate and latency metrics from Datadog and subsequently release the service to production. Deployments are automatically rolled back when the success rate falls below the defined success rate metric thresholds.
• Simplified Configuration – Configuration has been simplified drastically and integrated within the CI/CD pipeline in the new architecture, thereby reducing configuration complexity, eliminating manual processes, and saving Developers time.
• More time to Focus on Innovation – With fully automated progressive delivery, the developers no longer need to spend time testing and releasing source code in production. Similarly, migrating from a Self-managed DevOps platform to the Managed Amazon EKS services lowered the DevOps platform’s infrastructure management burden on the engineering team. This helps developers spend more time focusing on building and testing new features and innovations.
• Cost reduction – Moving from self-managed Amazon EC2-based architecture to the Amazon EKS cluster reduced the cost of operations through shared nodes and improved pod density. The previous architecture was using 200 nodes of Amazon EC2 instances. The same workload was moved to a 50 nodes Amazon EKS cluster. Furthermore, custom applications (Vanaheim and Jenkins) were retired, further reducing the costs.

Conclusion

In this post, you see how OfferUp embarked on the journey to modernize its DevOps platform to support its growth and developers’ velocity. The key factors that drove the modernization decisions were the ability to scale the platform to support the automated testing of features in production, the faster release of new features, cost reduction, and to facilitate future innovation. The modernized DevOps platform on Amazon EKS also decreased the ongoing operational support burden for engineers, and the scalability of the design opens up a lot of headroom for growth.

We encourage you to look into modernizing your existing CI/CD pipeline on Amazon EKS with the Flagger progressive delivery mechanism. Amazon EKS removes the undifferentiated heavy lifting of managing and updating the Kubernetes cluster. Managed node groups automate the provisioning and lifecycle management of worker nodes in an Amazon EKS cluster, which greatly simplifies operational activities, such as new Kubernetes version deployments.

In the next part of the series, you’ll discover how to implement Flagger and Gloo Edge Ingress Controller on Amazon EKS to automate the release process for applications running on Kubernetes.

Further Reading

Journey to adopt Cloud-Native DevOps platform Series #2: Progressive delivery on Amazon EKS with Flagger and Gloo Edge Ingress Controller

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